1. Field of the Invention
The present invention pertains generally to cable terminals and more specifically to a cable terminal which is capable of connection with a standardized device connector and selective interconnection of the cables.
2. Discussion of the Background of the Invention
In the computer industry, specialized tag cables are required for connecting communication cables from a CPU to a control unit and/or a peripheral device. Tag cables comprise tag-in and tag-out cables which are both connected to a single cable terminal. This single cable terminal may utilize plug connectors which allow the tag-in and tag-out cables to be conductively connected. Termination procedures in the cable terminator are tedious and time consuming because of the necessity to attach two separate cables. In many cases this requires the soldering of two wires to a single pin which is difficult and many times produces an improper connection. Consequently, a cable terminal is needed which allows quick and easy termination of two ribbon cables and is also capable of selectively interconnecting the two ribbon cables.
Examples of inventions relating to cable terminals and ribbon cables are disclosed in the following:
______________________________________ U.S. Pat. No. Inventor Date ______________________________________ 3,371,250 E. A. Ross et al. Feb. 27, 1968 3,447,120 S. Rask et al. May 27, 1969 3,476,870 E. A. Ross Nov. 4, 1969 3,479,565 E. A. Ross et al. Nov. 18, 1969 3,495,025 E. A. Ross Feb. 10, 1970 3,627,903 Plummer Dec. 14, 1971 3,639,716 Rasmussen Feb. 1, 1972 3,654,380 Tatum et al. Apr. 4, 1972 3,909,508 E. A. Ross Sept. 30, 1975 3,984,622 E. A. Ross Oct. 5, 1976 4,352,531 Gutter Oct. 5, 1982 4,415,216 Narozny Nov. 15, 1983 Berg Electronics Wilding Oct. 25, 1978 Du Pont Bulletin #1260 Berg SLT/MST Oct., 1983 Connector System ______________________________________
The Narozny patent discloses the use of a channel receiving U-shape bar 48 which receives ground wires, as illustrated in FIG. 5. Relief is provided to the ribbon cable by providing an arcuate bend in the cable which engages closing channels, as illustrated in FIG. 3.
The Gutter patent discloses a common ground elements which utilizes a helical spring, as illustrated in FIG. 3, which selectively engages ground wires 54. Signal wires 52 selectively engage appropriate contacts 20, 22. Stress relief is provided by a serpentine housing 44, as shown in FIG. 5.
The Rasmussen patent discloses a transfer switch located at the terminating end of the cable assembly. The transfer switch engages a printed circuit panel to provide selective activation of connection paths.
The disclosure by Wilding discusses the conventional use of a paddle board as an interface between a terminal connector and a cable. The Wilding design eliminates the use of a paddle board. Wilding uses a buss bar assembly in which all of the ground wires are bent backwards and soldered thereto, as illustrated in FIG. 5. A serrated surface, as illustrated in FIG. 1, provides strain relief.
The Du Pont bulletin discloses a cable terminal utilizing a paddle board and provides strain relief as disclosed on Page 9. The remaining patents pertain to woven ribbon cable construction.
As is apparent from these references, ribbon cables have been used for sometime to transmit data over a number of channels simultaneously. Cable terminals have been used in conjunction with ribbon cables to provide a conductive connection to standardized device connectors used on devices such as computers and peripheral devices in the computer industry. Standardized device connectors may be provided on various ports of computer terminals, CPUs, controller boxes, printers and other such devices in the computer field. Additionally, standardized device connectors are commonly used throughout the electronics, industry and especially in the communications industry. Hence, it is of importance to provide a cable terminal having a terminal connector which is compatible with standardized device connectors so that the cable terminal may be readily used to make conductive connections between various devices.
Numerous problems have existed in providing a cable terminal which provides easy and quick termination of the ribbon cable in a cable terminal device which provides strain relief between the ribbon cable and the various connections made within the cable terminal, and which allows disassembly of the cable terminal if conductive connections are broken or improperly made within the cable terminal. For example, strain relief has been provided in prior art cable terminals by the use of a potting material to fill the cable terminal voids and hold the ribbon cable securely within the cable terminal. The disadvantage with such devices is that the potting material prevents disassembly of the cable terminal so that the cable terminal cannot be repaired if a conductive connection is improperly made or becomes broken. Additionally, selection of the potting material must be made with great care since shrinkage during curing can cause conductive connections to break. The inability to disassemble and repair cable terminals results in a very high trash rate for cable terminals constructed in this manner.
Additionally, many cable terminals require soldering of signal and/or ground wires to specific pins of the terminal connector which is an expensive and time-consuming process. The systems may be restricted to a spatially oriented connection which limits the flexibility of connecting specific connectors to various pins of the terminal connector. Other systems allow connection of both signal and ground wires to any desired pin of the terminal connector. In these systems, however, mistakes can easily be made in the termination process resulting in signal and ground wires being connected to incorrect pins.
Insulation displacement cable terminals have been used to overcome problems associated with the time required in performing the termination process. These systems, however, are usually spatially aligned cable terminals which require a spatial in-line connection between the terminal connector and the conductors of the ribbon cable. Consequently, these systems do not provide the ability frequently required to connect various signal and ground wires to different pins on the terminal connector. These problems have been overcome to some extent by the use of printed circuit (PC) boards which allow connection of the ribbon cable to any desired output pin on the terminal connector, while maintaining the in-line spatial position of the connecting points of the ribbon cable to the PC board. However, the disadvantages of quick termination are lost connectors since prior art PC board connectors have required a significant amount of time to make discreet terminations of both ground and signal wires.